Erythropoietic action of dexamethasone on the anemia associated with an experimental chronic renal failure

Partially nephrectomized anemic uremic rats were injected with dexamethasone phosphate (10, 50 and 500 micrograms/kg/day), i.p., and erythropoietin (5 U/day), s.c., for 10 days. A marked and usually significant stimulatory effect on erythropoiesis was seen in all uremic animals treated. Administration of erythropoietin and dexamethasone produced a pronounced increment in hemoglobin, hematocrit and circulating reticulocytes. The increase in red blood cell production was also evident through the generally increased absolute numbers of nucleated erythroid cell precursors per milligram of bone marrow. The highest increases were seen in the erythropoietin treated uremic rats. A dose effect correlation was apparent in uremic rats receiving 3 different doses of dexamethasone. Dexamethasone may stimulate erythropoiesis in our anemic uremic rats through a previous augmentation of erythropoietin production in the residual renal mass. A synergistic permissive effect of dexamethasone increasing the sensitivity of the erythropoietin-responsive cells to erythropoietin in bone marrow is also quite possible.